Health care professionals routinely perform various types of microbial tests on patients using parenterally-obtained patient bodily fluids. Contamination of parenterally-obtained bodily fluids by microbes may result in spurious microbial test results. Spurious microbial test results may be a concern when attempting to diagnose or treat a suspected illness or condition. False positive results from microbial tests can cause a patient to be unnecessarily subjected to one or more anti-microbial therapies, such as anti-bacterial or anti-fungal therapies, which may cause anguish and inconvenience to the patient, as well as produce an unnecessary burden and expense to the health care system.